The present invention relates to a filling device adapted for wetting and/or filling a component provided with an undercut, as well as to a method of filling and/or backfilling the component with a flowable filler.
More particularly, the present invention relates to a filling device which is adapted for filling, backfilling or wetting a component provided with an undercut, where the angle of application and, therefore, the flowing direction of the filler can be adjusted by way of a deflecting unit. The present invention further relates to a method of filling and backfilling a component having an undercut with a flowable filler, where the filling of the area having the undercut takes place by way of a deflecting unit which is adjustable with respect to the angle of application. The invention can naturally also be used on components which have a different (not undercut) geometry.
In the prior art, different fields of application of filling devices are known which guide a flowable filler into a component or receptacle. Various industries use a variety of methods for filling their products and goods with PUR foam or the like. For example, to mention just a few application examples, the filling with a flowable filler is used in the packaging industry in order to fill boxes, cardboard boxes, vessels, cans, tubes and packages.
Another typical use for a filling device is found in the automotive industry such as for interior component parts in an automobile. Many of the products are shaped, for example, by means of a deep-drawing process and are additionally filled or backfilled with a PUR foam or a filler. For reasons of stability and assembly, diverse basic shapes require a foaming process in which the cavities are completely filled, for example, by use of a polyurethane foam.
Particular problems arise when viscous material is used as the filler. When a viscous or generally flowable filler is metered into a component, air may, for example, be enclosed in cavities, which results either in an insufficient filling of the component or simply in a rejecting of the merchandise. For example, when voids or cavities are produced in undercuts, which were insufficiently filled with filler, the component to be filled, for example, an instrument panel, will not be provided with the required stability or the latter may collapse or be dented at the concerned location.
Furthermore, process-caused difficulties may occur because, in the event of an insufficient filling of a component, it cannot be excluded that the filler may overflow and, in addition, the filling device may be soiled. These circumstances are particularly significant in the case of viscous materials since, as a result of their relatively high surface tension, these fillers have a tendency to adhere to one another, and to stay glued to the filling device with which they come in contact.
It is also difficult to completely or sufficiently fill and/or wet geometric shapes that are to be to be filled having undercuts, particularly those which have undercuts with areas that are difficult to reach. From the prior art, methods are known, for example, where the filling device is equipped with a nozzle that can be moved back and forth in order to better be able to fill possibly different filling levels. Thus, European Patent Document EP 0773905 B1 illustrates a filling device having a nozzle that can be moved back and forth.
From German Patent document DE A-2610396, a device is known for the metered filling of a particular highly viscous paste from a storage vessel into a cylinder-shaped filling vessel by means of a measuring cylinder connected with the storage vessel by way of a feeding pipe. The paste is introduced into the measuring cylinder under pressure by way of a multiple spigot, and a measuring piston, which has a measuring piston rod and can be moved in the measuring cylinder. The measuring piston, after the switching of the two-way spigot, presses the paste, which was metered and filled in the measuring cylinder determining the filling volume, by way of a delivery pipe into the filling vessel.
Furthermore, in the prior art, methods are known wherein a filling device has an outlet tube from which filler runs into the component to be filled. These devices known from the prior art have the disadvantage that undercuts and areas that are difficult to reach, in the case of complex component geometries, are not sufficiently wetted or filled by filler exiting from the outlet tube. As a rule, the flowable filler runs perpendicularly, thus in the vertical direction, out of a mixing head provided at the filling device. In this case, turning the outlet nozzle or the outlet tube in the desired direction presents a problem because, for example, in the case of an automated production, depending on the application case, degrees of axial freedom are not sufficiently available for rotating and moving the mixing head or, for example, because of its geometry, the mixing head cannot be swiveled into the desired position.
Particularly with respect to robots increasingly used in the automobile industry, the problem has to be solved that, as a result of geometrical limits and limited axial degrees of freedom, a robot-operated filling device can be used only inadequately or not at all for complex components.
It is therefore an object of the invention to provide a filling device and a method, which overcome the above-mentioned disadvantages and, in particular, are suitable for wetting and/or filling a component provided with an undercut with a flowable filler according to a requirement.
This and other objects are achieved by a filling device according to the present invention. It is the basic idea of the present invention to provide a filling device which has an adjustable deflecting unit for changing the direction of flow of the flowable filler at the mixing head, preferably adjacent to the outlet tube of the flowable filler, so that the filler released from the outlet tube can be deflected into an intended direction of flow and can be directed particularly into areas having undercuts.
According to the invention, a filling device is therefore provided which is adapted for wetting and/or filling a component provided with an undercut, the filling device having a mixing head for mixing a flowable, particularly curable filler, as well as having an outlet tube at the mixing head for feeding the flowable filler to or into a filling space of the component, and further having an adjustable deflecting unit for changing the outflow direction F into a direction of flow F′ deviating therefrom. As a result, it is achieved that the filler material exiting from the outlet tube 4 can be deflected into an intended direction of flow F′. In a simplest embodiment, an adjustable deflecting unit can therefore be mounted below the outlet tube 4, from which the flowable filler exits, by means of which deflecting unit, the direction of flow of the filler can be influenced. In this manner, the delivery angle of the filler at the mixing head can be adjusted and, by way of the deflecting unit, filler can thereby be directed to areas provided with undercuts or to cavities. According to the invention, the component can therefore be filled by way of the adjustable deflecting unit. This can advantageously take place without any moving of the mixing head relative to the component.
In a preferred embodiment of the invention, the filling device may be constructed such that the adjustable deflecting unit is arranged below the outlet tube. It is thereby ensured that the flowable filler directly flowing out of the outlet tube can be directed to the desired filling space during the curing period without any special constructive measures. Typical process times for applying and filling are in the range of a few seconds to approximately one minute.
The filling device is preferably provided with an adjusting device on which the deflecting unit is arranged, in order to be able to adjust the orientation of the deflecting unit in one or more spatial directions. Particularly preferably, the adjusting device may be set by way of a control unit as a function of the position of the outlet tube relative to the space to be filled as intended in its orientation. In this manner, without any movement of the filling device with respect to the component, the direction of flow F of the flowable filler can take place to a desired location.
In a particularly preferred embodiment, the adjusting device is constructed such that the deflecting unit, preferably directly fastened to the latter, can be adjusted by rotating or swiveling about an angle of rotation α. As a result, it is ensured that the deflecting unit can distribute the flowable filler in the plane, for example, by rotating about a defined angle α. The mixing head can preferably also be moved in one or more spatial axes, so that, as a result of the combination of axial and rotating movements, complex component geometries can also be filled.
It is further preferred that at least one servo motor be coupled with the adjusting device in order to be able to implement the deflecting device and thereby the deflection of the filler jet in one or more spatial directions, F, F′, F″.
In particular, it is preferable for the deflecting unit to be able to be positioned in an arbitrary orientation with respect to the outlet tube, so that also complex component geometries can be filled by way of a static mixing head (i.e. a mixing head that cannot be moved back and forth). It is particularly preferable for the adjusting devices to be controllable by way of high-speed servo motors via a control unit.
In a particularly preferred embodiment, the surface of the deflecting unit has an anti-adhesion layer. In this case, the deflecting unit may be completely or partially coated with the anti-adhesion layer. The anti-adhesion layer should be designed such that the anti-adhesion effect is present with respect to the flowable filler. In this respect, exchangeable deflecting units may be provided which are equipped with different anti-adhesion layers, depending on which filler is used. If the deflecting unit is covered by an anti-adhesion layer in the entire exposed area with which it comes in contact with the flowable filler, a cleaning device can additionally be provided at the filling device in order to remove excessive residues of adhering filler from the deflecting unit at regular intervals. Such a cleaning may, for example, take place inline by use of a cleaning solvent from a solvent nozzle or by use of compressed-air cleaning This means that a cleaning operation can be carried out without removing the deflecting unit.
In a particularly preferred embodiment, the filling device is adapted for use with flowable PUR foam (polyurethane) as the filler.
In a further advantageous embodiment, the filling device is characterized in that the anti-adhesion layer at the deflecting unit is constructed either as a Teflon layer or as a PP layer. Teflon has an anti-adhesion effect with respect to various fillers and adhesives.
The invention further provides a method of filling and/or backfilling a component provided with an undercut with a flowable filler by using the above-described filling devices.
According to the invention, at least the following process steps are carried out:
(a) providing a component with an undercut for filling and/or backfilling with a flowable curable filler;
(b) feeding filler to the component through the outlet tube; and
(c) adjusting the deflecting unit before and/or during the filling of a component such that the filler flowing out of the mixing head is deflected in its direction of flow F by the deflecting unit into a direction of flow F′ such that the filler flows into the area having the undercut and fills this area as intended.
Advantageously, the method according to the invention is carried out in an automated manner. The adjusting of the deflecting unit is implemented by an adjusting device which can be set by a servomotor, which adjusting device is coupled with the deflecting unit, whereby the adjusting device or the deflecting unit coupled thereto can be set in its orientation in an automated manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.